While exposure to sunlight may have some benefits, particularly the healthy appearance of a tan, ultraviolet radiation has substantial detrimental effects. The ultraviolet radiation can cause rapid aging and hardening of the skin, much like the tanning of leather. In addition, the ultraviolet radiation can cause severe erythmia, which in severe cases can be physically debilitating. Of particular concern, the ultraviolet radiation can cause DNA damage, which can lead to skin cancer or other cellular proliferative diseases. Skin cancer is the most prevalent of all cancers and is among the most preventable forms of cancer. Basal cell carcinoma is very common among those with fair skin and hair, but while rarely metastasizing can spread to bone. Malignant melanoma develops on the skin of about 35 thousand Americans annually, resulting in about 7 thousand annual deaths. Finally, squamous cell carcinoma, which is found on the ear, face, lips and mouth, is the second most common skin cancer in Caucasians, resulting in about 2.3 thousand deaths annually. UV radiation can also result in severe eye damage, leading to corneal bums, retinal bums, pingueculae and pterygium, cortical cataracts and macular degeneration. Cataracts are the major cause of visual impairment, with UV exposure being among the leading causes. Worldwide, 17 million people are blinded by cataracts, with nearly 1.5 million cataract extractions being performed annually in the United States.
Children, elderly, immunocompromised individuals, individuals with skin disorders, e.g. lupus erythematous patients, or others particularly susceptible or sensitive to ultraviolet radiation are particularly vulnerable to the injuries and disorders resulting from UV radiation. These susceptible individuals should have the capability of being warned about overexposure. In many cases, individuals rely on a suntanning screen which absorbs ultraviolet light. However, these screens and lotions are lost over time due to sweat, abrasion, exposure to water, and the like. Under these circumstances, the protection is lost and the person is subjected to unwanted ultraviolet radiation. UV protective coatings are available for eye ware. However, individuals have no convenient way of knowing the level of protection they are receiving. Also, UV lens coatings cannot protect against stray light which enters around the glasses.
There is a need for practical UV detection devices, which can be conveniently used and carried, so that they are available when the need arises. A number of photochemical systems have been described in the literature to act as dosimeters for ultraviolet light. See for example, U.S. Pat. Nos. 5,581,090; 5,028,792,; 3,710,115 and references cited therein. Also, devices have been made available, such as a card, UV Card, available from the South Seas Trading Co., and a UV meter, called SafeSun, available from Online Catalog.
However, to ensure that there is wide acceptance of the product, a UV sensor should be small and non-intrusive, waterproof and durable, useful in conjunction with a sunscreen, easy to store and disposable, easy to use and interpret and provide a consistent and accurate registration of UV radiation.
Devices and compositions are provided for integratively detecting ultraviolet exposure of skin. Devices and compositions comprise a carrier and a photochromic substance which changes color upon exposure to ultraviolet light. Particularly, diacetylenes are used in a form which adheres to the skin or eye ware, which can be removed when exhausted or desired. The devices are in convenient forms which encourage their use, being readily carried, conveniently packaged, non-intrusive, disposable and easy to interpret.
Integrating ultraviolet detection devices and compositions are provided. The devices and compositions allow for continuous monitoring of the ultraviolet radiation during the period of testing or exposure and ready removal once the period of testing or exposure has ended. For application, the devices are positioned so as to be retained during the period of testing or exposure and then readily removed afterwards. Therefore, the devices will for the most part be elastomeric and/or adherent. The devices are semi-permanent at the site at which they are placed, being removable without injury to the underlying substrate, usually skin. The devices also find application with eye ware.
The devices, while taking somewhat different forms, fulfill the characteristics of indicating the level of irradiation, providing a warning when the total irradiation has exceeded a safe amount, are easy to use and interpret, easy to store and readily disposable, small and non-intrusive, so as to be easily carried and stored on a person, waterproof and durable, can be used with a sunscreen and attractive to encourage use. In addition, the devices for placement on the skin will be transparent, so that they do not result in untanned portions of the skin, until the dye has substantially darkened. In addition, the devices may be coated with sun tan lotions, oils and creams, so that the devices may accurately record the amount of UV radiation to which the skin is exposed.
For the elastic bands, any elastomeric material which is not irritating to the skin and compatible with the photochromic agent may be employed. The elastomer will be substantially transparent or of sufficiently small dimension as not to leave a readily observable band upon tanning. Elastomers include: polyisobutylene, ethylenepropylene copolymers, polyisoprenes, polybutadienes, etc. Elastomers may be selected to absorb any sun tan protective coatings, much as the skin will absorb the coatings to varying degrees. These elastomers may be formed in bands or ribbons, generally having thicknesses of about 0.5 mm to about 5 mm, using not more than about 3 mm and may have the same width or be wider, depending upon the design and shape of the band. The band may be continuous or be joined by a link or clasp. If desired, a UV opaque cover may be employed, particularly one which is scored. By having the cover scored, individual portions of the cover may be removed, so that a single band may be used repeatedly, until the entire band has been exposed and exhausted. The cover may be paper or plastic, which will be able to withstand the conditions under which it is used. The band size or diameter is selected to fit snugly around a body part, such as a finger, wrist, forearm, bicep, anlde, or the like.
The elastomeric device may be preformed and combined with the photochromic agent, e.g. impregnated, painted, coated, sprayed, etc., or may be formulated with the elastomeric material and appropriately molded, extruded, cast, etc. The elastomeric device can be preformed, followed by impregnation with a solution of the photochromic agent, conveniently in combination with a polymer which aids in the coating and/or entry of the photochromic agent and retention in the elastomer. Polymers which may be employed include acrylic and styrene polymers, rubbers, and the like. Various solvents may be employed which will soften, but not dissolve, the elastomer and allow for impregnation of the elastomer with the photochromic agent. The solvent which is selected should be volatile, having a boiling point at ambient pressure above ambient temperature and less than about 100xc2x0 C. and residues of the solvent should not be irritating to the skin. The solvent will soften the surface of the elastomer or may impregnate the elastomer to a portion of the thickness of the elastomer, but will normally not dissolve the elastomer, so that upon volatilization of the solvent, the elastomeric device will be in substantially the same form as originally. When coating the elastomeric surface, the coating solvent will usually provide for impregnation of the photochromic agent into the elastomer or provide a polymeric protective coating which retains the photochromic agent on the surface of the elastomeric device. Illustrative solvents include: chloroform, diethyl ether, ethyl acetate, butanone, tetrahydrofuran, toluene, dichloromethane and the like. The concentration of the photochromic agent will be sufficient to provide a visual change in color of the elastomer upon exposure to UV radiation and may vary depending upon the nature of the elastomer, the photochromic agent, and the like. Generally, the concentration would be in the range of about 10 to 500 mg/ml, preferably from about 50 to 250 mg/ml. If a polymeric agent is also present, this may be present in from about 10 to 500 mg/ml, more usually from about 50 to 200 mg/ml. Conveniently, various addition or condensation polymers may be used, such as acrylic, vinyl, polyalkylene, polyesters, polyether polymers.
After impregnation, the solvent will be evaporated, using vacuum, elevated temperatures, ambient conditions, or the like. During the treatment and thereafter during storage, the elastomeric devices should be protected from ultraviolet light, conveniently by being stored in an opaque container which does not transmit ultraviolet light or covered with an opaque cover.
One can provide for determining gradations of irradiation, by using varying amounts of the photochromic agent. Thus, by varying the amounts within the range indicated previously, one can provide for detecting different levels of exposure. For example, one may have a series of formulations with 50 mg/ml, 100 mg/ml, and 200 mg/ml, where the formulations are present at different sites of the device, where each will be exposed to the same amount of UV radiation. The darkness of the color generated by exposing the photochromic agent to irradiation can also be used to judge the amount of irradiation. Depending on the structure of the device, the photochromic agent may be present as a line, band, design, message, two-dimensional figure, or the like.
Instead of an elastomer, a non-elastomeric film, such as a tape, decal, or label, may be employed. The film is or has an adhesive suitable for adhering to the epidermis, including fingernails. Except for those epidermal areas which are not readily affected by UV radiation, e.g. fingernails, the film will be transparent. The film may be combined with the photochromic agent in a variety of ways. The film may be impregnated with the solution of the photochromic agent as described above. Alternatively, the photochromic agent may be applied as an ink to the surface of the film, whereby the photochromic agent becomes bound to the film. Various permanent inks or ink matrices which are commercially available may be employed, where the photochromic agent will be mixed with the ink, which ink may be clear (free of other dyes) or be colored with a color that does not interfere with the color development of the photochromic agent. The ink may be painted on to the film substrate by any convenient means, coating, spraying, printing or the like. The concentration of the photochromic agent for impregnation or coating will generally be about the same as the concentration range described above for the elastomer treating solutions.
Adherent devices will normally be adhered to a layer from which the adherent layer may be readily removed while still retaining the adhering layer to the photochromic agent containing film. A wide variety of protective layers are available, as exemplified with Bandaids(copyright), label or decal materials, medical grade tapes, layers of adhesive tape, and the like. Alternatively, one can use an adhesive which can be separated from the surface of the device, when the device is in a roll.
The tapes may take a variety of forms, being opaque, such as adhesive tapes used for covering injuries, or clear, such as novelty tapes. A number of adhesives may be used which have acceptance in other situations, where the adhesive will strongly adhere to the substrate surface, but the tape may be removed by pulling the tape away from the surface. The tapes may come in a variety of sizes, being relatively small. The clear tape is preferred to allow for a more even tanning of the skin and minimally intrusive appearance. Usually tapes will vary in length from about 0.5 to 3 cm and in width from about 0.2 to 2 cm. The thickness of the layer containing the photochromic agent will be sufficient to allow the color change to be readily detected within the context of its use. Depending on the concentration of the photochromic agent, the required thickness will vary, generally varying in the range of about 0.1 to 1000 xcexc, more usually 10-100 xcexc.
Alternatively, the film may be a decal, which may be applied to the skin, where the decal will usually be at least partially colored so that its presence can be readily detected. The decal will be a preformed film, which will adhere to the skin when pressed against the skin, much as the adhesive tape. In some instances, the decal may require wetting before applying the decal to the skin. It may take a variety of geometric or odd shapes, being in the shape of figures, such as animals, objects, etc., where portions may be colored with a design, which design may be augmented by the development of the photochromic agent. The photochromic agent may result in a design, where the design may have different concentrations of the photochromic agent, so that the design will change as increasing areas of the design become developed. In this way a range of exposure to UV radiation may be determined. Alternatively, the agent may be printed adjacent to colored reference zones which indicate the degree of exposure compared to the darkness of the agent. These zones may be very small, so as to minimize the variation in tan or may be selected to provide a message which the wearer desires.
By virtue of the color change of the photochromic agent, various messages may be printed. By having a contrast between the region in which the photochromic agent is present and the remaining background, a message can be provided related to the status of the UV radiation or other information. Thus, one could print letters with the photochromic agent and provide a background the same as the photochromic agent, but not the same as when the photochromic agent has undergone a color change. Alternatively, one can provide that the message disappears, by having the background similar to the photochromic agent when it has became colored. One can also provide various colors as standards, as the region of the photochromic agent deepens in color. The standards can be related to various levels of UV radiation as described above. When using areas of different concentrations of the photochromic agent, one can provide for almost continuous gradations of UV radiation exposure, between the different concentrations and different standard colors. Transparent coatings or films that block UV light to varying degrees may be placed over areas of the photochromic agent to give differential sensitivities to exposure. These layers may be clear plastic films or clear glasses and may incorporate SPFs or other UV screening compounds.
The devices should have retentivity of the various protective sun coatings, so as to mimic the exposure of the skin. To that extent, the sun screens which are used should be compatible with the device. The film may be porous or non-porous to absorb the sun screen to an acceptable depth. The film should be wet by the sun screen in an analogous manner to the skin. Various plastics may be modified to provide the desired properties, such as chemical or physical modification, use of specific monomers to modify the characteristics of the bulk monomer, or thin coatings of a layer compatible with both the underlying substrate and the sun screen formulation.
One may also provide for various formulations which provide adherent coatings to a body surface, such as the skin, fingernails, or the like. For this purpose, one may use formulations such as fingernail polish formulations, e.g. acrylic paints, combined with the photochromic agent where the nail polish may be clear or colored with a color which does not interfere with the detection of the photochromic agent. A thin layer of the fingernail polish may be coated on one or more fingernails, so that upon UV exposure, the fingernails will turn colored. Alternatively, a hydrophobic composition may be employed, such as a balm, lotion, or the like, where various wax based formulations may be employed having from about 50 to 99 weight percent of a hydrophobic agent, e. g. hydrocarbons, hydrogenated oils, fatty acid esters, etc. Various additives may be included for texture, organoleptic properties, stability, or the like. These include such conventional additives as liposomes, polymerized liposomes, plastic microparticles, protein mixtures, cosmetic formulations and those used in balms.
The photochromic agent may be formulated with a sunscreen lotion as an emulsion, where the photochromic agent is encapsulated in droplets, including liposomes, which break down on spreading on the skin. The breakdown of the droplets results in a strongly adhering film, which will adhere to the skin under the UV radiation protective agent. Various polymers described previously, including celluloses, may be employed in the droplets. Exemplary formulations are described in U.S. Pat. Nos. 5,543,136; 4,897,259; 4,184,978 and 3,895,104. Alternatively, the photochromic agent can be an integral part of the liposome (e.g. diacetylenic lipid), such that the liposome can be both part of the liposome matrix and be the indicator of interest.
The photochromic agent may be readily mixed with the formulation to provide a stick, paint or lotion which formulation when applied to the skin will permit the photochromic agent to strongly adhere to the skin.
In each of these cases, the method of applying the photochromic agent and the base it is mixed with allows for its strong adherence and ready removal of the photochromic agent containing product by convenient means, well known in the literature. Nail polishes may be removed by gentle scrapping or with nail polish remover, balms, e.g. ChapStick(copyright), and other coatings with soap, tapes and decals by pulling off or scraping, or the like.
The photochromic agents of the subject invention are diynes (conjugated diacetylenes), particularly acid, ester, urethane, amide, nitrile, and alcohol monomers of at least about 8 carbon atoms, and not more than about 36 carbon atoms, more usually from about 12 to 30 carbon atoms. The acetylenic groups will generally be displaced from the terminal carbon atoms by at least 1 carbon atom. Various derivatives of the functional groups of the diynes can serve to modify the properties of the diynes for use in a particular formulation. For further information concerning these compounds, see U.S. Pat. Nos. 5,685,641; 5,622,872; 5,618,735 and references cited therein, whose disclosures are herein incorporated by reference as to their more complete description of the monomers and their preparation and derivatives. These compounds are readily formulated as the monomers with a wide variety of formulations, without special requirements, except that they be protected from ultraviolet radiation. They can be dissolved in a wide variety of solvents, mixed with various polymers, and incorporated with different agents, so as to provide for stably dispersed compositions. Upon exposure to ultraviolet radiation, the compositions turn light blue to a black metallic luster.
The subject devices, particularly as clear adhesive films, find use to protect the eye against UV radiation, by using the film in conjunction with the lense of eyeglasses. In this case, one may determine the extent to which the eye has been exposed to ultraviolet light which has come through the lens and stray light which enters from outside the eyeglasses. Conveniently, the sensing film may be placed on the inside of the lens of the glasses, so that the wearer may be able to judge instantly or continuously the level of sun exposure within the eye glassxe2x80x94eye cavity. A light blue color will begin to appear upon mild sun exposure, while the color would deepen upon prolonged or more intense exposure. In addition, as discussed previously areas of different concentration of the photochromic agent may be present, so as to provide a graduation of exposure. Various films may be employed which are clear, such as acrylics, polyalkylenes, polyvinyl ethers and esters, etc., which can be coated with a clear adherent layer. The film may then be adhered to a corner of the lens and monitored during exposure to UV radiation.